Magnetohydrodynamic stability analysis of the pedestals of ASDEX Upgrade plasmas

openThe high confinement mode (H-mode) dramatically improves the confinement properties of present tokamak plasmas and is therefore the scenario envisioned for future fusion reactors. The main characteristic of this scenario is the formation of a pedestal, a zone of steep temperature and density gradients, at the edge of the plasma, by means of a transport barrier. The height of the pedestal is limited by the onset of edge localised modes (ELMs), quasi-periodic explosive instabilities at the plasma edge which expel particles and energy on millisecond time-scales. While ELMs in present day machines pose no danger, when scaled to a fusion reactor device they are predicted to cause significant damage to the machine components. As such, the understanding and exploitation of alternative regimes with high confinement, but without ELMs, is of significant interest. The onset of an ELM can be described by magnetohydrodynamic (MHD) stability codes. The aim and project of the current thesis carried out at Max-Planck-Institut für Plasmaphysik (IPP) in Garching (Germany), involves the automation of a workflow which runs codes to test the pedestal MHD stability, such as MISHKA, starting from a standardised set of experimental information. In addition, the HELENA code is employed as a high resolution equilibrium solver through the calculation of the Grad-Shafranov equation for a toroidal axisymmetric plasma. Once the workflow is implemented, it is applied to a database of experimental data from the ASDEX Upgrade tokamak to study the properties of the pedestal through stability diagrams. It is particularly important to provide an estimate of the distance to the MHD stability boundary in the various ELM-free regimes to understand how robust these regimes are and the margin a given regime has before a large ELM is triggered. Various deuterium and helium plasma discharges are studied in this regard.The high confinement mode (H-mode) dramatically improves the confinement properties of present tokamak plasmas and is therefore the scenario envisioned for future fusion reactors. The main characteristic of this scenario is the formation of a pedestal, a zone of steep temperature and density gradients, at the edge of the plasma, by means of a transport barrier. The height of the pedestal is limited by the onset of edge localised modes (ELMs), quasi-periodic explosive instabilities at the plasma edge which expel particles and energy on millisecond time-scales. While ELMs in present day machines pose no danger, when scaled to a fusion reactor device they are predicted to cause significant damage to the machine components. As such, the understanding and exploitation of alternative regimes with high confinement, but without ELMs, is of significant interest. The onset of an ELM can be described by magnetohydrodynamic (MHD) stability codes. The aim and project of the current thesis carried out at Max-Planck-Institut für Plasmaphysik (IPP) in Garching (Germany), involves the automation of a workflow which runs codes to test the pedestal MHD stability, such as MISHKA, starting from a standardised set of experimental information. In addition, the HELENA code is employed as a high resolution equilibrium solver through the calculation of the Grad-Shafranov equation for a toroidal axisymmetric plasma. Once the workflow is implemented, it is applied to a database of experimental data from the ASDEX Upgrade tokamak to study the properties of the pedestal through stability diagrams. It is particularly important to provide an estimate of the distance to the MHD stability boundary in the various ELM-free regimes to understand how robust these regimes are and the margin a given regime has before a large ELM is triggered. Various deuterium and helium plasma discharges are studied in this regard

Caratterizzazione dei parametri operativi dello strumento NISP della missione Euclid

Nel presente lavoro di tesi si introducono gli elementi descrittivi della missione spaziale Euclid e la strumentazione di bordo, in particolare ci si sofferma sul ciclo di osservazione e sulla descrizione dello strumento NISP. Si procede con l'analisi di dati di un test effettuato il 9-10 febbraio 2020. Il test fa parte di una campagna di test svolta nei mesi di gennaio e febbraio per validare lo strumento NISP prima della sua integrazione sul satellite. L'obiettivo è verificare che lo strumento esegua la sequenza di operazioni nelle tempistiche definite, assicurando così la riuscita della survey ed una corretta funzionalità dello strumento.ope

Fundamentals of heterogeneous photocatalysis ; and, Consequences of inorganic and organic UV sunblocks on DNA

Titanium dioxide is a highly photoactive catalyst used extensively to abate and detoxify polluted waters, air, and soils. It is also commonly employed in commercial sunscreen lotions as a physical filter to block UVA/UVB sunlight radiation, designed to protect people from sunburns and skin cancers. The thesis is two-dimensional. Part A deals with fundamental studies of photocatalysis. Part B addresses more practical considerations of the use of titanium dioxide in suncreams. The thesis addresses the fundamentals of Heterogeneous Photocatalysis to provide additional understanding of the activity of TiO 2 , and of the (primary) events occurring during the photocatalytic process. A protocol is developed for measuring photochemical quantum yields, Z, in heterogeneous media. Turnover quantities and the nature of photocatalysis are treated mathematically. The spectral dependence of quantum yields and wavelength-dependent selectivities of photocatalysts are examined for the first time. Of import, reactions occurring at the TiO 2 particle surface involve hot charge carriers that do not relax down the conduction and valence band electronic manifolds as fast as conventional Wisdom had predicted. Further, the thesis focuses on the genotoxic effects of TiO 2 on DNA. The spectroscopic features of TiO 2 , make it an excellent UVA/UVB sunblock. We demonstrate that, when commercial TiO 2 specimens are illuminated with UV radiation, hydroxyl radicals are generated, which damage supercoiled DNA plasmids and human skin cells as evidenced by single- and double-strand breaks, and kill yeast cells. Passivation of the titania particle surface reduces the photoactivity, of titanium dioxide with profound impact on the photooxidation of phenol. Also, damage to DNA., human skin cells and yeast cells is dramatically attenuated by modified titania samples, thus making them safer for use in sunscreen lotions. Moreover, the modified specimens completely retain their UVB/UVA absorption characteristics. Contrary to manufacturers claims, commercial sunscreen lotions exposed to simulated sunlight are not photostable. Preliminary spectroscopic and photochemical studies on active ingredients in various solvents are reported. Results indicate that the organic chemical UV filters photodegrade on exposure to simulated sunlight in relatively short time. The nature of the solvent and the presence of oxygen influence the photodegradation. Formation of singlet oxygen is suspecte

Oltre i «corpi umani in fuga». La sfida della progettualità esistenziale nelle pratiche degli operatori dell’accoglienza nei servizi Sprar a Bologna

Il presente articolo analizza la figura dell’operatore dell’accoglienza nei Servizi di protezione per richiedenti asilo e rifugiati (Sprar) da una prospettiva pedagogica. Attraverso 19 interviste con operatori di una cooperativa sociale di Bologna (2017) e il dialogo con la letteratura pedagogica di riferimento, il mio contributo indaga le ragioni del divario tra richieste istituzionali e le pratiche dell’accoglienza. L’approfondimento che segue riflette sull’identità professionale dell’operatore dell’accoglienza, sulla necessità, così come viene percepita dai miei interlocutori, di ritrovare – nel proprio ruolo e nelle pratiche svolte all’interno dei servizi in cui operano – un «mandato sociale» teso a superare interventi a carattere emergenziale e assistenziale, se non espressamente a dirigersi verso azioni capaci di creare progetti di reale inclusione sociale. In linea con le direzioni auspicate a livello nazionale, l’obiettivo di questo studio è quello di rivolgere una particolare attenzione alle dinamiche relazionali, che rappresentano un nodo centrale del lavoro degli operatori dell’accoglienza, rintracciando le competenze pedagogiche necessarie all’accompagnamento della persona nella costruzione di un nuovo progetto di vita. Muovendosi all’interno di una complessa rete che coinvolge numerosi attori – i beneficiari del progetto, l’équipe di riferimento, le agenzie pubbliche e i servizi territoriali – è possibile rilevare come il ruolo e le competenze dell’operatore richiedano di essere definite ed esplorate per fare emergere una nuova consapevolezza nelle pratiche e negli obiettivi dei servizi per l’accoglienza dei richiedenti asilo e rifugiati.This article investigates the role of social workers in the Italian reception system of asylum seekers and refugees (Sprar) from a pedagogical perspective. Drawing from 19 interviews with caseworkers from a social cooperative in Bologna (2017) and from a review of pedagogical literature, this article highlights the gap between institutional guidelines and practices on the ground. The following in-depth analysis reflects on the professional identity of the case worker and on their perceived need to find in their role and in their daily practices a wider «social mandate» aimed at overcoming an emergency approach and moving towards social inclusion. In line with Sprar institutional objectives, the purpose of this study is to focus on relational dynamics, which represent a central node of social work: these should be based on the pedagogical skills necessary to accompany the asylum seeker in the construction of a new life project. Moving within a complex network of numerous players – the beneficiaries of the project, the team, public agencies and local services – it is possible to see how the role and skills of the case worker must be defined and explored to stimulate new awareness in the practices and the objectives of reception services for asylum seekers and refugees

L’esperienza del Master in “Educatore nell'accoglienza e inclusione di migranti, richiedenti asilo e rifugiati” dell’Università di Bologna: tra ricerca, formazione e diritti umani.

The increase in migratory flows, from the North Africa Emergency (2011-2013) to the recent Ukraine Emergency, questions the host societies and requires a structured and far-sighted intervention response. In this context emerges the demand for training of professional figures able of operating, with competence and professionalism, to facilitate the process of inclusion and reception of adult migrants, minors, and those with specific vulnerabilities. With these aims, the Master in "Educator in the reception and inclusion of migrants, asylum seekers and refugees" of the University of Bologna was born in 2018, now in its second edition. The co-planning with the third sector, the University's networking with the territory and the interdisciplinary perspective with which the Master was built have allowed to support the practice and structure the professional epistemology of these figures.L’incremento dei flussi migratori, dall’Emergenza Nord Africa (2011-2013) fino alla recente Emergenza Ucraina, interroga le società di approdo e richiede una risposta di intervento strutturata e lungimirante. In questo contesto emerge la domanda di formazione di figure professionali capaci di operare, con competenza e professionalità, per facilitare il processo di inclusione e accoglienza di migranti adulti, minori e con specifiche vulnerabilità. Con questi intenti, nasce nel 2018 il Master in “Educatore nell'accoglienza e inclusione di migranti, richiedenti asilo e rifugiati” dell’Università di Bologna, oggi alla sua seconda edizione. La co-progettazione con il terzo settore, la messa in rete dell’Università con il territorio e la prospettiva interdisciplinare con cui il Master è stato costruito hanno consentito di sostenere la pratica e la strutturazione della epistemologia professionale di queste figure

La lingua dell’accoglienza. Riflessioni sull’insegnamento dell’italiano L2 per adulti stranieri

L’articolo affronta il tema dello sviluppo dell’autonomia nell’educazione del migrante adulto, focalizzandosi in particolar modo sui processi di insegnamento dell’italiano come lingua seconda. L’obiettivo principale è quello di ricercare possibili strategie per orientare l’azione formativa verso la costruzione di un percorso politico-pedagogico trasformativo. Questo permette al migrante di acquisire competenze e capacità critiche per superare l’emarginazione e avviare da protagonista il proprio processo di integrazione nella società d’accoglienza. In tale direzione, si è tentato di attivare connessioni tra ambiti disciplinari diversi, facendo dialogare il lessico glottodidattico con le teorie pedagogiche di stampo critico e il problematicismo pedagogico, provando a tradurre in prassi le istanze prodotte da tale colloquio. Oggi occorre ripensare le metodologie di insegnamento di italiano L2, ponendo lo studente al centro del processo di apprendimento, favorendo lo sviluppo di pensiero critico e di competenze relazionali per incentivare una reale autonomia e un arricchimento esistenziale reciproco

Identification of calcium sensing receptor (CaSR) mRNA-expressing cells in normal and injured rat brain

Calcium sensing receptor (CaSR), isolated for the first time from bovine and human parathyroid, is a G-protein-coupled receptors that has been involved in diverse physiological functions. At present a complete in vivo work on the identification of CaSR mRNA-expressing cells in the adult brain lacks and this investigation was undertaken in order to acquire more information on cell type expressing CaSR mRNA in the rat brain and to analyse for the first time its expression in different experimental models of brain injury. The expression of CaSR mRNAs was found mainly in scattered cells throughout almost all the brain regions. A double labeling analysis showed a colocalization of CaSR mRNA expression in neurons and oligodendrocytes, whereas it was not found expressed both in the microglia and in astrocytes. One week after kainate-induced seizure CaSR was found in the injured CA3 region of the hippocampus and very interestingly it was found up-regulated in the neurons of CA1-CA2 and dentate gyrus. Similarly, 1 week following ibotenic acid injection in the hippocampus, CaSR mRNA expression was increased in oligodendrocytes both in the lesioned area and in the contralateral CA1-CA3 pyramidal cell layers and dentate gyrus. One week after needle-induced mechanical lesion an increase of labeled cells expressing CaSR mRNA was observed along the needle track. In conclusion, the present results contribute to extend available data on cell type-expressing CaSR in normal and injured brain and could spur to understand the role of CaSR in repairing processes of brain injury